Such an air spring/shock absorber unit, a so-called gas spring strut, is known in various forms, such as from German patent publications 3,526,156 and 3,810,011 as well as from U.S. Pat. No. 4,325,541. Such a gas spring strut is discussed by way of example with respect to FIG. 3.
A shock absorber having an impact disc is shown in FIG. 4 and is also indicative of the state of the art.
All conventional gas spring struts have separate pressure compartments which are charged with pressurized air or a hydraulic medium. In this context, a problem is present with respect to the sealing of the pass-throughs provided for the piston rods.
High manufacturing costs are associated with conventional pressure-loaded dampers in order to achieve the required tightness of the piston chamber movable relative to the piston rod, (for example, the required induction hardening at HCR 56.+-.4, machining and polishing for a profile depth of R.sub.t .ltoreq.0.2 .mu.m, at least 20 .mu.m hard chrome coating in order to obtain a surface hardness of HCR 70.+-.2).
Because of the wear of this seal, the service life of the damper or of the hydropneumatic spring strut is limited.